Self-conscious Blake Shelton won't take shirt off

It’s that time of year when celebs are photographed daily showing flesh in exotic, aquatic, farflung locales. But not Blake Shelton.

The country crooner and his “The Voice” co-star girlfriend Gwen Stefaniposed in pictures published Monday kissing in a pool with a headline blaring, “CAUGHT Getting Intimate In A Swimming Pool!” But while Stefani wore a teeny bikini, Shelton was in the sun-drenched pool in a giant maroon T-shirt.

“He is so sensitive about his weight,” a source told us about Shelton’s pool look. “You will never see him shirtless.”

Shelton recently dropped a reported 30 pounds after splitting with Miranda Lambert — he called it the “divorce diet.” But a source said that even on the set of “The Voice,” “backstage . . . he always keeps his dressing room closed. At photo shoots, he will not change on set. He goes back to his dressing room whenever he needs to take his clothes off.” But, “He is not in bad shape. He’s just so shy about showing off his body.”

Another source said that during shoots for the NBC show, “Adam Levine will take off his shirt — and his pants — in the studio. Christina Aguilera also doesn’t even care.”

“If you get dressed up the right way, it should be fitted,” he said, wearing a tux for a pal’s wedding. “But when things are fitted to me, it’s hard for me to disguise man boobs and gut and all that stuff, so it’s all sticking out!” He’s told “Today,” “I lost some weight and now I’m like, ‘How did I do that? I need to do that again!’”

The same day that Shelton and Stefani’s pool pics surfaced her washboard-abbed ex-husband, rocker Gavin Rossdale, appeared in his own paparazzi shots running topless in Hawaii, naturally.